Tar mines alter the Canadian landscape toroughly (photo: Garth Lenz)

Tar sands, also called bituminous sands, is loose sand containing a of mixture of clay and water saturated with a dense and viscous form of petroleum, technically referred to as bitumen. They are found in very large quantities in Canada, Kazakhstan and Russia. The estimated worldwide deposits are far more than estimated deposits for petroleum. The extraction process is expensive, but due to high oil prices tar sands development has seen a big increase the last years. Tar sand mines treathen natural habitats and landscapes as seen on the picture above.